The interface between natural teeth and chewing gum is not one of tooth enamel (calcium phosphate) but rather mucin which is a slippery proteinaceous film covering natural teeth. However, it appears that artificial teeth and dentures, which are usually formed of acrylic polymers, polystyrene, polyvinyl chloride, polyvinyl esters (Luxene), hard rubber (Vulcanite), and the like, do not wet as effectively as natural teeth, and will not readily be coated with mucin. Accordingly, where many chewing gum compositions will not adhere to natural teeth, they will adhere to artificial teeth and dentures.
Various additives for chewing gums have been suggested to reduce or eliminate the problem of chewing gum adhering to dentures and artificial teeth, such as lecithin as disclosed in U.S. Pat. Nos. 2,197,719, lanolin as disclosed in U.S. Pat. No. 2,197,718 and silicone oils as disclosed in U.S. Pat. No. 2,761,782. U.S. Pat. No. 3,255,018 to Comollo discloses the use of water-soluble hydrolyzable tannin, such as tannic acid or polymer-tannic acid adducts, in combination with type A or B gelatin water-containing hydrophilic polymer gels.
U.S. Pat. No. 1,977,059 to Hatherell discloses a method of making a chewing gum base produced from resin, rubber, and other materials examples of which include fine fibers of a material such as wood or asbestos or cotton or silk. The latter materials are ostensibly present to impart cohesivity to the gum base.
Larger cud volume is a desired characteristic in chewing gums, since after the extractable materials are consumed during chewing larger volume of the leftover cud results in better and easier chew. This is especially true in bubble gum, since small cuds will not allow blowing bubbles. Accordingly, increasing the cud volume without increasing the gum base is a very desired characteristic in chewing gums.